The software manages a sender's accreditation, letting it segment mail into different classes. PowerMTA 3.0 also lets a sender monitor its reputation through blocking reports and management of Internet service provider bounce messages.

"We've been focused on sender issues from the beginning," said Bill Karpovich, senior vice president of marketing and strategy at the 5-year-old company. "We now see the opportunity to add more value."

Port25, Ellicott City, MD, sells its software to e-mail service providers, such as Silverpop and Responsys, and businesses doing their e-mail marketing in-house, including Travelocity and Volvo.

Despite AOL's recent decision to part ways with Microsoft in the development of its Sender ID authentication protocol, most e-mail industry analysts think e-mail identity systems will be in place at ISPs by the end of the year.

Karpovich said the development of multiple standards would only heighten the need for senders to focus on compliance.

"It's complex now, and it's only going to get more complex," he said. "You'll have more standards, and you'll have versions of standards."